package com.sardine.base.http;


import com.sardine.base.utils.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * Created by wangchao16 on 2016.6.2 0002.
 */
public class RSAUtils {
    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {

        //得到一个加密算法
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        //生成公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        //生成私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        //设置公钥
        keyMap.put(PUBLIC_KEY, publicKey);
        //设置私钥
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /**
     * <p>
     * 用私钥对信息生成数字签名
     * </p>
     *
     * @param data 已加密数据
     * @param privateKey 私钥(BASE64编码)
     *
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return Base64.encode(signature.sign());
    }

    /**
     * <p>
     * 用公钥对校验数字签名
     * </p>
     *
     * @param data 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @param sign 数字签名
     *
     * @return
     * @throws Exception
     *
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        byte[] keyBytes = Base64.decode(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(Base64.decode(sign));
    }


    /**
     * <p>
     * 公钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公钥加密
     * </p>
     *
     * @param data 源数据
     * @param publicKey 公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 私钥加密
     * </p>
     *
     * @param data 源数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }


    /**
     * <P>
     * 私钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param privateKey 私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = Base64.decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 获取私钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return Base64.encode(key.getEncoded());
    }

    /**
     * <p>
     * 获取公钥
     * </p>
     *
     * @param keyMap 密钥对
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return Base64.encode(key.getEncoded());
    }

    static String publicKey;
    static String privateKey;

    public static void main(String[] args) {
        try {
            //得到公钥，私钥
            Map<String, Object> keyMap = RSAUtils.genKeyPair();
            //得到公钥
            publicKey = getPublicKey(keyMap);
            publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCM/SLq4WxFsmbQ1Ub6Zmx/bAjmDvhNTSYvPP8fL04GPHcn+sy2U6+KMSBs9OTd6D7ZZE0GQB5NFqrqWs2m3xi1GZ2CMR/OYyw/tNP7xZqg53abT62wpcZNQl+cwFme4rLBNYKiXqlhikPGCXGme/m3x949eaY3jq05q3NPKIwlLQIDAQAB";

            //得到私钥
            privateKey = getPrivateKey(keyMap);
            privateKey = "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";
            System.err.println("公钥:" + publicKey);
            System.err.println("私钥:" + privateKey);
            String source = "630391773000022";
            System.out.println("加密前文字：" + source);
            byte[] data = source.getBytes();
            //----------------------------------------------------------------------------- 公钥加密，私钥解密
            //公钥加密文件
            byte[] encodedData = encryptByPublicKey(data, publicKey);
            String str = Base64.encode(encodedData);
            System.out.println("返回前端:"+str);
            //私钥解密密文
            byte[] decodedData = decryptByPrivateKey(Base64.decode(str), privateKey);
            String target = new String(decodedData);
            System.out.println("解密后文字:" + target);
            //-----------------------------------------------------------------------------私钥加密，公钥解密
            //用私钥加密
            encodedData = encryptByPrivateKey(data, privateKey);
            str = Base64.encode(encodedData);
            System.out.println("返回前端:"+str);
            //私钥解密密文
             decodedData = decryptByPublicKey(Base64.decode(str), publicKey);
            target = new String(decodedData);
            System.out.println("解密后文字:" + target);


            //----------------------------------------------------------------------------- 私钥数字签名，公钥对比

            String sign=sign(data,privateKey);
            System.out.println("数字签名："+sign);
            System.out.println(verify(data,publicKey,sign));


        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
